#include <bits/stdc++.h>
#include <atcoder/all>

using namespace std;
using ll = long long;
#define rep(i, s, t) for (ll i = s; i < (ll)(t); i++)
#define all(x) begin(x), end(x)
template <class T> bool chmin(T& x, T y) {
	return x > y ? (x = y, true) : false;
}
template <class T> bool chmax(T& x, T y) {
	return x < y ? (x = y, true) : false;
}

void solve() {
	int n, k;
	cin >> n >> k;
	vector<int> a(n);
	rep(i, 0, n) cin >> a[i];
	if ((n + 1) / 2 < k) {
		cout << "Impossible\n";
		return;
	}
	vector<ll> dp1(k + 1, -1e18);
	vector<ll> dp2(k + 1, -1e18);
	dp1[0] = dp2[0] = 0;
	for (int x : a) {
		auto ndp2 = dp2;
		rep(i, 0, k + 1) chmax(ndp2[i], dp1[i]);
		vector<ll> ndp1(k + 1, -1e18);
		rep(i, 0, k) chmax(ndp1[i + 1], dp2[i] + x);
		swap(dp1, ndp1);
		swap(dp2, ndp2);
	}
	cout << max(dp1[k], dp2[k]) << '\n';
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout << fixed << setprecision(15);
	int t = 1;
	// cin >> t;
	while (t--) solve();
}